Communication control apparatus, communication system, and method

Abstract

A communication control apparatus according to the present disclosure includes: a control means for selecting a predetermined wireless communication apparatus closest to a terminal from among a plurality of wireless communication apparatuses based on a position of the terminal and positions of the plurality of wireless communication apparatuses, identifying an estimated position of the terminal when a data signal is to be transmitted from the predetermined wireless communication apparatus based on the position and a velocity vector of the terminal when a reference signal (RS) is received by the predetermined wireless communication apparatus, and controlling the predetermined wireless communication apparatus to transmit the data signal with antenna directivity being oriented in a direction from the predetermined wireless communication apparatus toward the estimated position of the terminal.

What is claimed is: 
     
         1 . A communication control apparatus comprising:
 at least one memory storing instructions, and   at least one processor configured to execute the instructions to;   estimate, for each of a plurality of wireless communication apparatuses, a signal delay amount from a terminal to an antenna of the wireless communication apparatus and a relative velocity between the terminal and the wireless communication apparatus based on a reference signal, which has been subjected to orthogonal time frequency space modulation, received from the terminal by each of the plurality of wireless communication apparatuses;   estimate a position and a velocity vector of the terminal based on positions of the plurality of wireless communication apparatuses, and the signal delay amount and the relative velocity estimated for each of the plurality of wireless communication apparatuses; and   select a predetermined wireless communication apparatus closest to the terminal from among the plurality of wireless communication apparatuses based on the position of the terminal and the positions of the plurality of wireless communication apparatuses, identifying an estimated position of the terminal when a data signal is to be transmitted from the predetermined wireless communication apparatus based on the position and the velocity vector of the terminal when the reference signal is received by the predetermined wireless communication apparatus, and control the predetermined wireless communication apparatus to transmit the data signal with directivity of the antenna being oriented in a direction from the predetermined wireless communication apparatus toward the estimated position of the terminal, wherein   a first frequency is used for a signal from the terminal to the wireless communication apparatus, and   a second frequency, which is higher in frequency than the first frequency, is used for a signal from the wireless communication apparatus to the terminal.   
     
     
         2 . The communication control apparatus according to  claim 1 , wherein the signal delay amount and the relative velocity are estimated based on a position in a delay-Doppler space of the reference signal when being transmitted from the terminal and a position in the delay-Doppler space of the reference signal when being received by the wireless communication apparatus. 
     
     
         3 . The communication control apparatus according to  claim 1 , wherein the at least one processor configured to execute the instructions to select the wireless communication apparatus that has received the reference signal with highest reception power as the predetermined wireless communication apparatus, instead of selecting the predetermined wireless communication apparatus closest to the terminal based on the position of the terminal and the positions of the plurality of wireless communication apparatuses. 
     
     
         4 . The communication control apparatus according to  claim 1 , wherein the relative velocity is obtained from a Doppler shift amount of the reference signal which has been subjected to the orthogonal time frequency space modulation. 
     
     
         5 . The communication control apparatus according to  claim 1 , wherein
 the antenna includes a plurality of antenna elements, and   each of the plurality of antenna elements is weighted to form the directivity.   
     
     
         6 . The communication control apparatus according to  claim 1 , wherein a downlink signal from the wireless communication apparatus to the terminal is subjected to single carrier modulation. 
     
     
         7 . The communication control apparatus according to  claim 6 , wherein an uplink time zone in which an uplink signal from the terminal to the wireless communication apparatus is communicated and a downlink time zone in which the downlink signal is communicated are alternately switched. 
     
     
         8 . The communication control apparatus according to  claim 1 , wherein the communication control apparatus and the plurality of wireless communication apparatuses are connected by an optical cable. 
     
     
         9 . A communication system comprising:
 a plurality of wireless communication apparatuses that communicate with a terminal; and   a communication control apparatus that controls the plurality of wireless communication apparatuses, wherein   each of the plurality of wireless communication apparatuses includes:   at least one wireless memory storing instructions, and   at least one wireless processor configured to execute the instructions to;   receive a reference signal, which has been subjected to orthogonal time frequency space modulation, transmitted from the terminal via an antenna; and   transmit a data signal with directivity of the antenna under control from the communication control apparatus,   the communication control apparatus includes:   at least one control memory storing instructions, and   at least one control processor configured to execute the instructions to;   estimate, for each of the plurality of wireless communication apparatuses, a signal delay amount from the terminal to the antenna and a relative velocity between the terminal and the wireless communication apparatus based on the reference signal received from the terminal by each of the plurality of wireless communication apparatuses;   estimate a position and a velocity vector of the terminal based on positions of the plurality of wireless communication apparatuses, and the signal delay amount and the relative velocity estimated for each of the plurality of wireless communication apparatuses; and   select a predetermined wireless communication apparatus closest to the terminal from among the plurality of wireless communication apparatuses based on the position of the terminal and the positions of the plurality of wireless communication apparatuses, identifying an estimated position of the terminal when a data signal is to be transmitted from the predetermined wireless communication apparatus based on the position and the velocity vector of the terminal when the reference signal is received by the predetermined wireless communication apparatus, and control the predetermined wireless communication apparatus to transmit the data signal with the directivity of the antenna being oriented in a direction from the predetermined wireless communication apparatus toward the estimated position of the terminal,   a first frequency is used for a signal from the terminal to the wireless communication apparatus, and   a second frequency, which is higher in frequency than the first frequency, is used for a signal from the wireless communication apparatus to the terminal.   
     
     
         10 . The communication system according to  claim 9 , wherein the signal delay amount and the relative velocity are estimated based on a position in a delay-Doppler space of the reference signal when being transmitted from the terminal and a position in the delay-Doppler space of the reference signal when being received by the wireless communication apparatus. 
     
     
         11 . A method comprising:
 estimating, for each of a plurality of wireless communication apparatuses, a signal delay amount from a terminal to an antenna of the wireless communication apparatus and a relative velocity between the terminal and the wireless communication apparatus based on a reference signal, which has been subjected to orthogonal time frequency space modulation, received from the terminal by each of the plurality of wireless communication apparatuses;   estimating a position and a velocity vector of the terminal based on positions of the plurality of wireless communication apparatuses, and the signal delay amount and the relative velocity estimated for each of the plurality of wireless communication apparatuses;   selecting a predetermined wireless communication apparatus closest to the terminal from among the plurality of wireless communication apparatuses based on the position of the terminal and the positions of the plurality of wireless communication apparatuses;   identifying an estimated position of the terminal when a data signal is to be transmitted from the predetermined wireless communication apparatus based on the position and the velocity vector of the terminal when the reference signal is received by the predetermined wireless communication apparatus; and   controlling the predetermined wireless communication apparatus to transmit the data signal with directivity of the antenna being oriented in a direction from the predetermined wireless communication apparatus toward the estimated position of the terminal, wherein   a first frequency is used for a signal from the terminal to the wireless communication apparatus, and   a second frequency, which is higher in frequency than the first frequency, is used for a signal from the wireless communication apparatus to the terminal.